Reciprocating piston type gas compressor



3 Sheets-Sheet l INVENTOR.

W. E. MICHENER ATTQR N EYS RECIPROCATING PISTON TYPE GAS COMPRESSOR May5, 1964 Filed June 23, 1961 .lll

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May 5, 1964 w. E. MICHENER RECIPROCATING PISTON TYPE GAS COMPRESSOR 3Sheets-Sheet 2 Filed June 23, 1961 1964 w. E. MICHENER 3,131,856

RECIPROCATING PISTON TYPE GAS COMPRESSOR Filed June 23, 1961 3Sheets-Sheet 3 l 6 777i INVENTOR.

ATTO NEYS.

United States Patent 3,131,856 RECIPROCATING PISTON TYPE GAS COMPRESSQRWilliam E. Michener, Milwaukee, Wis., assignor to Vilter ManufacturingCorporation, a corporation of Wisconsin Filed June 23, 1961, Ser. No.119,669 Claims. (Cl. 230-438) This invention relates generally toimprovements in the gas compression art, and it relates morespecifically to improvements in the construction and operation of gascompressors of the reciprocating piston type.

The primary object of the present invention is to provide variousimprovements in the valving and control mechanism of reciprocable pistongas compressors, whereby the construction of such machines isfacilitated and the efficiency is enhanced.

It has heretofore been common commercial practice to utilize compressorshaving several stages each embodying a cylinder and a piston coopreatingwith a set of annular suction and discharge valves, and provided withcapacity control mechanism of opening selected suction valves in orderto unload the corresponding stages. 7 These valves are usually formed ofrelatively thin but durable sheet metal and of large diameter since thesuction valve of each stage or compression until ordinarily surroundsits cylinder adjacent to its outlet end and the discharge valve islocated closely adjacent to but beyond this cylinder end so as to reducethe clearance space to a minimum, and each of these valves is constantlyurged toward closed position by an annular series of helical compressionsprings. While this general type and arrangement of annular valves haslong been in use, it has been difficult to properly guide the samerelative to their annular inlet and discharge ports while reducing theclearance spaces to a minimum, and it was also quite tedious to applyand remove these prior valve assemblages.

Then, too, the capacity control mechanisms of these prior assemblagesand which were adapted to lift the suc tion valves from their seats inorder to unload the compressor were also relatively complicated anddifficult to install; and these prior mechanisms were thereforerelatively unreliable in operation and required considerable attentionin order to maintain them in proper operating condition.

It is therefore an important object of the present invention to providesimple and effective means for facilitating installation of such valvesand of the unloading devices associated therewith so as to insure mosteflicient functioning of these compressors with least attention.

Another important object of this invention is to provide far morereliable guiding of the annular plate valves of such gas compressors inorder to eliminate excessive clearance space and to maintain both theinlet and discharge valves properly centralized relative to their seatsand ports.

A further important object of the invention is to provide a simplifiedand improved capacity control device and mechanism for transmittingmotion therefrom to the annular suction valve for the purpose ofinsuring most efiective unloading of the compressor.

Still another important object of the present invention is to provide animproved val-ving and unloading assemblage for gas compressors, wherebyvarious parts of these mechanisms may be readily pro-assembled and thedevices may be installed as complete units within the compressorhousings in proper relation to the individual cylinders.

These and other more specific objects and advantages of the inventionwill be apparent from the following detailed description:

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A clear conception of the features constituting the present improvementsand of the construction and operation of a typical multiple cylindercompressor embodying the invention may be had by referring to thedrawings accompanying and forming a part of this specification whereinlike reference characters designate the same or similar parts in thevarious views.

FlG. 1 is a diagrammatic side view of a multi-cylinder piston type ofgas compressor embodying four pairs of radial cylinders each havingtherein a piston reciprocable from a common crank shaft adapted to berevolved by an electric motor;

FIG. 2 is an erdarged transverse approximately vertical section throughthe crankcase and through one of the cylinders and valve assemblages ofa compressor such as shown in FIG. 1, with one of the capacity controlunits illustrated in elevation;

FIG. 3 is a further enlarged longitudinal approximately vertical butfragmentary section taken centrally through one pair of adjoiningcylinders and through a portion of the corresponding capacity controlmechanism, the section being taken along the line 3-3 of FIG. 1;

FiG. 4 is a slightly reduced top view of one of the improved capacitycontrol units showing the same applied to sections through a pair of thecompressor cylinders along the line 4-4 of FIG. 3;

FIG. 5 is a transverse section through the capacity control unit orunloading device of FIG. 4, taken along the line 55 of FIG. 6; and

FIG. 6 is an approximately vertical section through the same capacitycontrol device, taken along the line 66 of FIG. 4.

While the invention has been illustrated and described herein as havingbeen embodied in a particular type of gas compressor especially adaptedfor refrigeration service and embodying eight reciprocable motor drivenpistons, it is not intended to necessarily confine the use of theimprovements to such a compressor; and it is also contemplated thatspecific descriptive terms employed herein be given the broadestpossible interpretation consistant with the disclosure.

Referring to FIGS. 1, 2, and 3 of the drawings, the gas compressorillustrated therein comprises in general, a main frame 9 having thereina suction chamber 10 communicating with a crankcase 10' in which acrankshaft 11 is revolvable by an electric motor 12; four pairs ofcylinders 13 mounted in the frame 9 and radiating from the axis of thecrankshaft 11; a piston 14 reciprocable within each of the cylinders 13by a connecting rod 15 attached to the crankshaft 11; an annular suctionvalve 16 surrounding the outer end of each cylinder 13 and coacting withinlet ports 17 which are communicable with the suction chamber 10 andwith the adjacent piston displacement chamber 18; an annular dischargevalve 19 coacting with an annular series of outlet ports 20 whichcommunicate with the adjacent chamber 18 of each cylinder 13 through ahead 21; a cover 22 enclosing each pair of heads 21 and communicatingwith a common compressed gas discharge space 23; and a capacity controlunit 24 cooperable with selected pairs of cylinders 13 and beingoperable to lift the suction valves 16 thereof in order to unload thecompressor.

The main frame is preferably formed of a sturdy integral casting andwhen the compressor is motor driven as shown in FIG. 1, the motor 12 andframe 9 may be mounted upon a foundation base 26 as illustrated. Eachcylinder 13 is provided with an integral flange 27 at its outer end inwhich the suction ports 17 are formed, and these cylinders and flangesare pressed into alined bores in the frame 9 and are firmly securedtherein. The annular suction and discharge valves 16, 19 are formed ofthin but durable sheet metal, and each suction valve in FIGS. 3 to 6inclusive.

16 is confined within a removable annular guard 28 secured to theadjacent cylinder flange 27 by cap screws 29 as in FIG. 3, and which hasan annular series of small helical compression springs 30 confinedtherein and coacting with the adjacent plate valve 17. Each cylinderclosure end head 21 is secured to another removable annular guard 31 bya bolt 32 as depicted in FIGS. 2 and 3,

and each of these guards also confines an annular series of smallhelical compression springs 33 which coact with the adjacent platevalve'19. Each discharge valve guard 31 and cylinder head 21 is normallyheld within and in snug engagement'with the adjacent normally stationarysuction valve guard 28 by means of a large and strong helical spring 34reacting against the adjacent cover 22; and these covers are detachablysecured to the frame 9 by cap screws 35.

It is important that the periphery of each annular suction valve 16cooperates with its guard 28 with minimum clearance and that theperiphery of each annular discharge valve 19 likewise cooperates withits guard 31, in order that these valves will be constantly centralizedwith respect to their ports 17, 29, respectively, and the'annular seriesof springs 30, 33 urge the'valves 16, 19 toward their seats. It'is alsonoteworthy that although the cylinder closure heads 21 are relativelythin and thus reduce the compression clearance to a minimum, these heads21 are amply reinforced against possible distortion by the heavy guards31 with which the heavy springs 34 coact; and the cap screws 29, 35enable the entire suction and discharge valve assemblages to beassembled externally of the frame 9 and applied as individual units tothe compressor in assembled condition or removed in like condition forinspection and possible renewal of Worn or broken valves 16, 19. i

' The improved capacity control units '24 which coact with selectedsuction valves 16 for the purpose of unloading the compressor aremounted upon a partition 37 which spans the crankcase but is subjectedto suction pressure on both sides, as shown in FIG. 2, but each of theunits 24 cooperates with both suction valves 16 of the selectedipair ofcylinders 13 in the manner illustrated Each unloading unit comprises ingeneral a guide member 38- having thereon a central bore39 and fourupright guide pins 40 disposed parallel to thisbore while two parallelupright pivot pins 41 are secured to the member 38 between the guidepins '40; a plunger 42 reciprocable within the bore 39 and having a rod43 rising upwardly between the pivot pins 41; a horizontal H-shaped yoke44 penetrated by and slidable along the pivot pins 41 and, beingconstantly urged in anupward direction by relatively heavy springs 45surrounding the shorter guide pins 40 and coacting with the member38 andthe yoke 44; a pair of levers 46 pivotally attached to the upperends ofthe pins 41 by pivots 47=and coacting at their opposite ends with theplunger rod' 43 and yoke 44 respectively; and means for transmittingmotion of the'yoke 44 to the adjacent suction valves 16 of the selectedpair of compression cylinders and pistons.

Gas under pressure derived from the discharge chamber of the compressoror from any other source, of control is admissible to the displacementchambers of the unloading unit plungers 42 through conduits 49, and arelatively light helical spring 511 coacts with the lower face of' eachplunger in order to eliminate lost motion in the leakage. The laterallyprojecting four prongs or arms of the H-shaped yoke 44 extend todiametrically opposed sides of the adjacent pair of cylinders 13 asshown in FIG. 4, and the free ends of these arms are adapted to coactwith rings 51 which surround and are slidable along the adjacentcylinder walls and carry annular sets of parallel rods 52 reciproc'ablethrough parallel holes in the adjacent cylinder flanges 27 and which areengageable with the corresponding suction valves 16 to lift them fromtheir seats and hold them open during unloading 4 v operations. Ahelical spring 53 surrounds each rod 52 between the adjacent cylinderflange 27 and the ring 51, and each ring is recessed internally toprovide a stop 54 cooperable with a snap ring 55 in order to limit thedown-' ward movement of the adjacent ring 51 as clearly shown in FIG. 3.

With the various parts of the compressor constructed as hereinabovedescribed, the several cylinders 13 with the rings 51 and snap rings 55applied thereto may be pressed Within the radially alined sets ofopenings in the frame 9 and properly positioned by means of stop rings57 as shown in FIGS. 2 and 3, and the pistons 14, connecting rods 15,crankshaft ll'and other accessories normally 34 may be assembled on aworkbench'and applied as complete units to their respective cylinders 13and secured in place with the aid of the cap screws 29, and the covers 722 and cap screws to finish the compressor instalfa j tion. These valveassemblages may also be just as readily removed for inspectionandposs'ible replacement of worn of time, and when assembled the valves16, 19 will always he maintained properly centralized with respect totheir annular ports 17, 20 by the guides 28, 31.

Dining normal operation of the improved compressor, the motor 12revolves the crankshaft ll-causing it to reciprocate the several sets ofpistons 14 in succession during each revolution of the cranks. Duringeach inward travel of the pistons'14, gas will be drawn from within thesuction chamber 16 through the ports 17 and past the suction valves 16into the corresponding displacement chambers 18; and when the compressoris operating at full capacity, outward travel ofeach piston 14 will'compress and deliver the gas admitted to its displacement chamber 18through the ports 20 and past the discharge valve 19 into the dischargeconduit 23. However, if the compressor is to be partially unloaded, thecapacity control unit 24 will function to automatically hold thecorresponding suction valves 16 from their seats during the dischargestroke of the adjacent pistons 14 thus preventing delivery of compressedgas from the cylinders 13 "with ing piston type of gas compressor whichis simple and eflicient and wherein the various parts may be readilyassembled and installed or removed when necessary. The valves 16, 19 areeffectively guided to prevent lateral shifting, and each cylinder hasminimum clearance space thereby enhancing the efiiciency of the unit,and the ports 17, 20 are usually formed as annular series of openings ina well-known manner. units 24 are also compact and durable in structureand can be conveniently installed, and the entire assemblage has provenhighly satisfactory and successful in commercial use especially asapplied to refrigeration systems.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is'regarded as theinvention.

I claim:

l. A gas compressor comprising,v a main frame, a cylinder mounted insaid frame and having abore and an integral external flange at one endthereof provided with a series of suction ports, a piston reciprocablewithin said bore toward and away from said flanged end, an an- Theimproved capacity control nular guide ring detachably secured to saidflange and forming an extension of said cylinder, said ring beingprovided with an annular recess facing said flange and said suctionports, the exposed inner periphery of said ring being tapered outwardlyto provide a frusto-conical seat surrounding an end of said cylinderbore, an annular suction valve disposed within the recess of said guidering and resiliently urged toward said cylinder flange to normally closesaid suction ports, a flat closure plate for said bore end having atapered peripheral edge seated on the frusto-conical seat of said guidering and having therein a series of discharge ports, an annular guidemember secured to said plate remote from said cylinder bore, said guidemember being formed with an annular recess facing said plate and saidsuction ports, an annular discharge valve disposed within the recess ofsaid guide member and resiliently urged toward said plate to normallyclose said discharge ports, a cover cooperable with said frame toprovide a compressed gas chamber, and resilient means interposed betweensaid cover and said guide member to detachably maintain said guidemember and said closure plate in position.

2. A gas compressor according to claim 1, wherein the resilient meansbetween the cover and the guide member for retaining the guide memberand the closure plate in position is a heavy compression spring seatedat one end on the guide member and at the other end on the cover.

3. A gas compressor according to claim 1, wherein the annular guidemember is secured to the closure plate by a single central bolt and theguide ring is formed with an outwardly extending lug cooperating withthe guide member to positively locate the same.

4. A gas compressor according to claim 1, wherein the main frame hascomplementary pairs of parallel cylinders mounted therein and each pairof complementary cylinders is enclosed by the cover.

5. A gas compressor according to claim 4, wherein the main frame isformed with aligned openings within which the cylinders are confinedwith the external flanges thereof snugly fitting the openings, theannular guide rings also being snugly fitted within said openings.

References Cited in the file of this patent UNITED STATES PATENTS247,857 Thompson Oct. 4, 1881 2,517,367 Winkler May 1, 1950 2,626,102Garland Jan. 20, 1953 2,638,265 Newton May 12, 1953 2,955,749 TomkowiakOct. 11, 1960 2,956,729 Nicholas Oct. 18, 1960 2,983,132 Hirsch Feb. 28,1961 3,000,553 Towers Sept. 19, 1961

1. A GAS COMPRESSOR COMPRISING, A MAIN FRAME, A CYLINDER MOUNTED IN SAID FRAME AND HAVING A BORE AND AN INTEGRAL EXTERNAL FLANGE AT ONE END THEREOF PROVIDED WITH A SERIES OF SUCTION PORTS, A PISTON RECIPROCABLE WITHIN SAID BORE TOWARD AND AWAY FROM SAID FLANGED END, AN ANNULAR GUIDE RING DETACHABLY SECURED TO SAID FLANGE AND FORMING AN EXTENSION OF SAID CYLINDER, SAID RING BEING PROVIDED WITH AN ANNULAR RECESS FACING SAID FLANGE AND SAID SUCTION PORTS, THE EXPOSED INNER PERIPHERY OF SAID RING BEING TAPERED OUTWARDLY TO PROVIDE A FRUSTO-CONICAL SEAT SURROUNDING AN END OF SAID CYLINDER BORE, AN ANNULAR SUCTION VALVE DISPOSED WITHIN THE RECESS OF SAID GUIDE RING AND RESILIENTLY URGED TOWARD SAID CYLINDER FLANGE TO NORMALLY CLOSE SAID SUCTION PORTS, A FLAT CLOSURE PLATE FOR SAID BORE END HAVING A TAPERED PERIPHERAL EDGE SEATED ON THE FRUSTO-CONICAL SEAT OF SAID GUIDE RING AND HAVING THEREIN A SERIES OF DISCHARGE PORTS, AN ANNULAR GUIDE MEMBER SECURED TO SAID PLATE REMOTE FROM SAID CYLINDER BORE, SAID GUIDE MEMBER BEING FORMED WITH AN ANNULAR RECESS FACING SAID PLATE AND SAID SUCTION PORTS, AN ANNULAR DISCHARGE VALVE DISPOSED WITHIN THE RECESS OF SAID GUIDE MEMBER AND RESILIENTLY URGED TOWARD SAID PLATE TO NORMALLY CLOSE SAID DISCHARGE PORTS, A COVER COOPERABLE WITH SAID FRAME TO PROVIDE A COMPRESSED GAS CHAMBER, AND RESILIENT MEANS INTERPOSED BETWEEN SAID COVER AND SAID GUIDE MEMBER TO DETACHABLY MAINTAIN SAID GUIDE MEMBER AND SAID CLOSURE PLATE IN POSITION. 